This invention generally relates to a system for automatically applying the brakes of a truck or tractor-trailer type vehicle for transporting volatile fluids during filling and emptying of the vehicle.
It is common practice to transport flammable or volatile fuels, such as for example liquid petroleum gas, gasoline, and the like, by tank-type tractor trailers or other large road vehicles utilizing tanks with hose connections for both filling and emptying the tanks. During such filling or emptying procedure, drivers have been known to drive away with the hoses connected causing the hoses to rupture. Because of the volative nature of these fuels, the consequences have been known to be catastrophic. Thus, it has been common to include with the vehicles, which are customarily equipped with air brakes, some form of safety brake system which applied the brakes beyond the control of the driver whenever the delivery hoses are connected. These known systems have used some means for exhausting the emergency line of the vehicle air brake system, but the arrangements used to achieve this result have included mechanical linkages which are susceptible to malfunction. Thus, in one such system connection of the delivery hose actuates a lever which opens one or more exhaust ports located in the emergency line through a mechanical linkage arrangement.
Applicant has succeeded in developing a system that positively locks the emergency brakes of the vehicle, whenever liquid is delivered to or from the vehicle tank, which has an exceptionally high degree of reliability, has no intricate linkage that can bind and wear out, and which is quite easy to install.
In a preferred embodiment of the invention, applicant's arrangement includes a port located at each of the fittings of the vehicle to which a delivery hose is connected for either filling or emptying the vehicle tank. This port is connected by a hose to the emergency line of the vehicle air brake system such that whenever the port is open to atmosphere the emergency line of the vehicle is exhausted and the emergency brakes are automatically applied. A cap is removably secured to the fitting and includes sealing means for sealing the port when the cap is tightly secured. To attach the delivery hose to the fitting, the cap must be removed which automatically unseals the port and applies the emergency brakes. With the cap removed, the driver is unable to move the vehicle.
Thus, it is a primary object of the invention to provide a system for automatically applying the brakes of the vehicle during filling or emptying operation of the vehicle tank, and which is exceptionally simple in structure and reliable in operation and which can be easily installed on existing vehicles.